This invention relates to an inlet vacuum valve having a unit controller for a vacuum sewerage system and, more particularly to, a mounting apparatus which facilitates easy mounting and removal of the unit controller of an inlet vacuum valve for a vacuum sewerage system.
Vacuum-operated sewerage systems of the prior art design and construction employ vacuum collection stations connected to a pipe network of sewer lines linked to remote a sewerage inlet point which serves one or more houses. Each inlet point has a vacuum operated valve which provides for intermittent admission of the accumulated sewage into the vacuum pipe network. A unit controller which operates the inlet vacuum valve in a predetermined pattern. The inlet vacuum valve acts as an interface between the vacuum sewerage system and the conventional gravity sewer lines associated with a house. The inlet vacuum valve and unit controller are contained in a below-grade pit where the vacuum and gravity connections are facilitated and where maintenance of the inlet vacuum valve and unit controller occurs. The general structure and method of operation of the inlet vacuum valve and unit controller are described in U.S. Pat. No. 4,171,853 (Cleaver, et al.); U. S. Pat. No. 4,373,838 (Foreman et al.) and U.S. Pat. No. 4,691,731. (Grooms et al.).
The controller unit for each of the inlet vacuum valves is a relatively sophisticated and complicated piece of vacuum-operated equipment. The unit controller is the piece of equipment which cycles the inlet vacuum valve to open at a predetermined time and pattern to allow accumulated sewage to pass into the associated vacuum pipe network for transport to the remote collection station. Installation of the unit controller has been on the upper housing of the inlet vacuum valve and has presented somewhat of a problem during an original installation, due to the tight quarters one must work in.
Occasionally, due to storms allowing water to enter fittings which are recently damaged and unexpected power failures, the unit controllers of an inlet vacuum valve fail to perform or do not perform in accordance with a predetermined pattern, and require field replacement by field service engineers or trained maintenance personnel. Unit controllers are often fastened to the upper housing of the inlet vacuum valve by a mounting arrangement which involves threading a plurality of stainless steel bolts into threaded stainless steel inserts found in the upper housing of the inlet vacuum valve. Often the field service personnel will have to conduct their service operations in a very unpleasant environment, due to weather conditions, or due to the cramped nature of the area where the inlet vacuum valves and unit controllers are located. Occasionally, the stainless steel inserts in the upper housing are misaligned when the original inlet vacuum valve has been originally manufactured and this misalignment causes problems for the field service personnel to make the proper physical connection required when replacing a unit controller that has failed.
Similarly, due to location of the unit controller on the top of the upper housing of the inlet vacuum valve, some of the threaded connections which have to be accomplished at the rear of the unit controller require a connection which cannot be viewed by the field service personnel. All of this is very time consuming for field service personnel who find themselves in a dirty, damp, smelly and cramped below grade environment where the inlet vacuum valve and unit controller are located.
Furthermore, as a result of the constant dampness and moisture condensation present, the stainless steel bolts and stainless steel inserts which hold the unit controller to the inlet vacuum valve will tend to become coated or oxidize over time or over the life cycle of the inlet vacuum valve due to ground water within the below grade chamber. This presents additional connection problems for the field service personnel to overcome.